Structures for use on both land and/or water as security barrier systems have been previously developed. Such structures generally intend to stop intruding objects, and range from thick, solid walls blocking the object's progress to secured areas for disabling the propelling mechanism of the object. These structures commonly exhibit noticeable shortcomings. First, these structures are often cumbersome and time-consuming to install and erect where desired. Second, to be used as a gate, they require a small tugboat or larger vessel to push and maneuver the gate into a closed position. Third, the physical connections are heavy and must be manually operated resulting in frequent injury and man overboard situations.
One solution providing an improved marine barrier is shown in FIGS. 1a-d and disclosed in U.S. Pat. No. 8,379,725, which is incorporated herein by reference in its entirety. Referring to FIGS. 1a-b, the marine barrier 400 includes two continuous pleated rows 401, 402 of first and second respective pluralities of buoyant panels 110, to form a diamond-shaped barrier. A plurality of outboard hinges 120 and a plurality of inboard hinges 420 elastically connect opposing sides of adjacent panels 110 to form two continuous pleated rows 401, 402, such that the hinges 120, 420 are arranged in first, second, and third substantially parallel rows.
A first plurality of impact cables 430 are attached to opposing ends of the first pleated row of panels 401 and pass through each of the hinges 120 in the first row of hinges 410a. A second plurality of impact cables 430 are attached to opposing ends of the second pleated row of panels 402 and pass through each of the hinges 120 in the third row of hinges 410c. In this particular version of the barrier, there are five impact cables 430 associated with each of the pleated rows 401, 402, and they are substantially parallel to each other. Impact cables 430 comprise, for example, steel wire rope.
Referring now to FIGS. 1c-d, when the barrier 400 is floating in a body of water 440 and a moving vessel (represented by arrow 450) impacts one or more of the first plurality of impact cables 430 attached to the first pleated row 401 of panels 110, the impact cables 430 deflect to transfer a force of the impact to one or more of the first plurality of panels 110 of the first pleated row 401, which in turn engage the water 440, and to one or more of the second plurality of panels of the second pleated row 402, which in turn engage the water 440, to transfer the force of the impact to the water 440 and arrest the motion of the vessel. The load path of the impact force of the moving vessel is shown by lines L, M, and N, representing the impact force as it moves from the impact cables 130 (lines L) to the panels 110 (lines M) and the hinges 120 and 420 (lines L and N).
Likewise, if a vessel impacts one or more of the second plurality of impact cables 430 attached to the second pleated row 402, the load path of the impact force will be similar, but in an opposite direction to lines L, M, N. Thus, during an impact the panels 110 are drawn in around the point of impact and engage the water to dissipate the impact force.
The marine barrier of FIGS. 1a-d is a vast improvement over previous barriers, as it has the unique ability to collapse into a retracted position along its length. In FIGS. 2a-d, the diagrammatic representation of how the marine barrier of FIG. 1 operates is shown. In the marine barrier gate 800, the first tow cable and the catenary cable are respectively permanently attached to the barrier 400c and the second buoy 640, and are long enough to be submersible. When the gate 800 is open these cables sit on the sea floor, and when the gate is to be closed the cables rise and come under tension (by operation of their respective winches) to expand and close the gate. To open the gate, the barrier 400c is pulled along the catenary cable, and when the gate is fully retracted, the cable tension is released by the winches and the two cables drop to the seafloor under their own weight.
As shown in FIG. 2a, a submersible tow cable 810 is fixedly attached to the second end hinge 421b of the second row of hinges 410b of barrier 400c, and is extendible by the first tow winch 640a to a position below a surface 820a of body of water 820 when the panels 110 of barrier 400c are in the retracted position; i.e., when the gate 800 is open. A submersible catenary cable 830 is fixedly attached to the second buoy 640 at attachment point 640d, and is extendible by the catenary winch 620a to a position below the surface 820a of the body of water 820 when the panels 110 of barrier 400c are in the retracted position.
As shown in FIGS. 2b-c, when the gate 800 is to be closed the submersible catenary cable 830 is reeled in by catenary winch 620a to a desired tension or length, so it will absorb catenary loads on the barrier 400c when the panels 110 are moved from the retracted position to the expanded position. The submersible tow cable 810 is then reeled in by first tow winch 640a to pull the barrier 400c across the gate span in the direction of arrow P (see FIG. 2C). The latch 640c of the second buoy 640 engages the second end hinge 421b to retain the barrier 400c in the expanded position. FIG. 2d shows the barrier 400c fully expanded, and the marine barrier gate 800 thereby closed.
When the barrier 400c is in the expanded position of FIG. 2d and it is desired to move it to the retracted position, the latch 640c of the second buoy 640 is disengaged from the second end hinge 421b of barrier 400c. The second tow cable 740 is then reeled onto the second tow winch 620b (see FIG. 2c), while the first tow winch 640a extends the submersible tow cable 810 to allow the second tow cable 740 to move the panels 110 from the expanded position to the retracted position in the direction of arrow Q. Meanwhile, the catenary winch 620a maintains a length or tension of the submersible catenary cable 830 such that the submersible catenary cable 830 absorbs catenary loads on the barrier 400c when the panels 110 are moved from the expanded position to the retracted position by operation of the second tow winch 620b. 
After the barrier 400c is retracted by operation of the second tow winch 620b, the first tow winch 640a further reels out submersible tow cable 810, which sinks under the surface 820a of the water 820; for example, to the sea floor. Likewise, the catenary winch 620a reels out submersible catenary cable 830, which sinks under the surface 820a under its own weight. The gate 800 is now open, as shown in FIG. 2a, and vessels can pass between the buoys 620, 640. Further, the gate 800 is reset and ready to be closed again when necessary.
Although barrier 800 has many advantages, the management of the cables and understanding of the position of the cables in the water column is not optimized for maximum effectiveness. In addition, the cable management system in these figures uses three cables and three winches which, disadvantageously, has high maintenance requirements.
There exists a need for a marine barrier with improved cable management for opening and closing the gate in a variety of environmental conditions and deployment sites and for helping ensure the cable/line is under tension.
Systems and technologies exist for transferring or moving a floating structure, such as a ferry or barge, across bodies of water. These systems typically employ a single line that spans the channel, with the structure connected to the line at some point in between. The structure is then moved by a combination of two winches, one that pays out the line, and a second opposing winch simultaneously pulling the structure and taking line in off the first winch.
The cable operation methods and technologies described in this document are inherently different than such systems for the following reasons, and are described in more detail in the following sections. In this application, two lines are employed of similar or different material, subjected to different tensions; the line is then brought down to the seafloor allowing clear passage of the channel using a variety of methods described herein, with the position of both cables known at all times and used to identify when the channel is clear for passage.